CN103725031B - A kind of extra dry red wine fructus corni extracts the technique of purplish red pigment - Google Patents

Abstract

The invention discloses a process for extracting jujube red pigment from dried jujube skin, which comprises the following steps: 1) taking the dried jujube skin and pulverizing it; 2) immersing the pulverized dried jujube skin into an alkaline solution and combining ultrasonic extraction to obtain Dried red jujube skin extract; 3) using absolute ethanol to remove polysaccharides from the extract; 4) centrifuging the polysaccharide-treated extract and passing it through an ultrafiltration membrane with a molecular weight cut-off of 25-35KDa to obtain the primary effluent 5) centrifuging the primary effluent again, and then passing through an ultrafiltration membrane with a molecular weight cut-off of 1-3 KDa to obtain the final effluent; 6) drying the final effluent to constant weight to obtain bouquet red pigment. Jujube red pigment is a natural plant pigment, which has no toxic and side effects on the human body and can be widely used in medicine, food, beverage, and high-grade cosmetics. The process of the invention is simple, the cost is low, and the extracted jujube red pigment has good stability, high purity and wide adaptability.

Description

A kind of process of extracting jujube red pigment from dry jujube skin

technical field

The invention relates to the field of food additives, in particular to a process for extracting jujube red pigment from dried jujube peels by using membrane separation technology.

Background technique

Jujube is a unique fruit in my country. It is sweet and delicious, rich in nutrition, edible and medicinal. It has many medicinal functions such as nourishing yin and kidney, strengthening the body, softening blood vessels, appetizing and invigorating the spleen. good name.

The annual output of jujubes in my country is as high as 1.3 billion kilograms, mainly through natural drying, and the dried jujubes enter the circulation market directly. However, the commercialization rate of jujubes is only about 30%, and nearly 30% of jujubes cannot enter the circulation market. These jujubes that cannot enter the circulation link are mainly defective fruits such as small fruit weight, bruised fruit, cracked fruit, and low maturity. Although they have lost their commodity value, they still have high nutritional content and suitable processing characteristics. A very small part is used by jujube processing enterprises, and most of them are turned into ashes in the fields, resulting in a serious waste of jujube resources. Dried jujube skin is rich in jujube red pigment. Compared with the extraction of other red pigments, the material cost can be greatly reduced, and the main component of jujube red pigment is flavonoids, which is natural, safe, non-toxic and harmless.

Membrane separation technology is a new separation and concentration method. There is no phase change in the separation and concentration process, so there is no thermal degradation of natural products. In addition, it can save energy and simplify the production process. It can be used in the extraction, separation, purification and Concentration and other aspects have good application prospects.

Utilizing membrane separation technology to extract jujube red pigment from dried jujube skin has the advantages of simple production process, low cost, good product stability and high purity. The product has broad market space both at home and abroad.

Contents of the invention

The object of the present invention is to provide energy-saving jujube pigment separation process.

The object of the present invention is also to provide a non-toxic and harmless jujube pigment separation process.

The object of the present invention is also to provide a high-purity jujube pigment separation process.

In order to achieve the above object, the present invention can provide the following technical solutions:

The invention discloses a process for extracting jujube red pigment from dried red jujube peels. The extract solution of dried red jujube peels after polysaccharide removal is passed through membrane filtration to separate the red pigments in the dried red jujube peels.

Preferably, in the described dried jujube bark extracting jujube red pigment technology, comprise the following steps:

1) take dry jujube skin, pulverize;

2) immersing the crushed dried red jujube skin into an alkaline solution, combined with ultrasonic extraction, to obtain an extract of dried red jujube skin;

3) using absolute ethanol to remove polysaccharides from the extract;

4) After centrifuging the polysaccharide-treated extract, pass it through an ultrafiltration membrane with a molecular weight cut-off of 25-35 KDa to obtain a primary effluent;

5) After the primary effluent is centrifuged again, it passes through an ultrafiltration membrane with a molecular weight cut-off of 1 to 3 KDa to obtain the final effluent;

6) Dry the final effluent to a constant weight to obtain boar red pigment.

Preferably, in the described dried jujube bark extraction process of jujube red pigment, the step 1) includes:

Wash the dried red dates first, then cook them at 100°C for 15-30 minutes, wash them with water to remove the jujube meat and other impurities, and obtain the jujube skins;

Soak in 1% to 5% (v/v) HCl for 8 to 12 minutes, the ratio of solid to liquid is 0.8 to 1.2: 18 to 22 (g/ml), wash to remove HCl, and dry at 35 to 50°C until Constant weight, crushed with a pulverizer, and sieved.

Preferably, in the process of extracting jujube red pigment from dried red jujube skin, cooking at 100°C for 30 minutes, soaking with 3% (v/v) HCl for 10 minutes, and a solid-liquid ratio of 1:20 ( g/ml), dried at 40°C to constant weight, and passed through a 40-mesh sieve.

Preferably, in the described dried jujube skin extracting jujube red pigment technique, described step 2) includes:

The ultrasonic power is 40~70w, the time is 45~60min, the temperature is 50~60℃, the ratio of material to liquid is 0.8~1.2:18~22 (g/ml), and 0.7~0.9% (w/v) NaOH solution To obtain the extract, centrifuge at a speed of 8000-10000 rpm for 25-35 minutes, discard the precipitate, and adjust the pH value of the supernatant to 70.

Preferably, in the process of extracting jujube red pigment from dried jujube skin, in the step 2), the ultrasonic power is 60w, the time is 45min, the temperature is 60°C, and the ratio of solid to liquid is 1:20 (g/ml) , using 0.8% (w/v) NaOH solution as the extracting liquid, centrifuged at 10000rpm for 30min.

Preferably, in the process of extracting jujube red pigment from dried jujube skin, the step 3) includes: the neutral supernatant is concentrated under reduced pressure at 50-60°C to 25-30% of the volume of the stock solution, and the stock solution is added Dehydrated ethanol with a volume of 70-75% is precipitated at -15-25°C for 30-60 minutes, centrifuged at a speed of 8000-10000 rpm for 25-35 minutes, and then the polysaccharide is removed to obtain an extract.

Preferably, in the process of extracting jujube red pigment from dried jujube skin, the neutral supernatant is concentrated under reduced pressure to the volume of the stock solution at a vacuum degree of -0.02 to -0.08 MPa and a temperature of 50 to 60°C. 25%, adding absolute ethanol with a volume of 75% of the original solution, precipitation at -20°C for 30 minutes, and centrifugation at 10,000 rpm for 30 minutes.

Preferably, in the process of extracting jujube red pigment from dried jujube skin, in the step 4), the polysaccharide-treated extract is centrifuged at a speed of 10000rpm for 30min, and the molecular weight cut-off is passed through an ultrafiltration membrane of 30KDa to obtain a primary effluent.

Preferably, in the process of extracting jujube red pigment from dried jujube skin, the primary effluent in step 5) is centrifuged at a speed of 10000rpm for 30min, and the final effluent is obtained by passing through an ultrafiltration membrane with a molecular weight cut-off of 2KDa. The effluent was dried at 40°C.

The beneficial effects of the present invention are:

The invention provides a process for extracting jujube red pigment from dried red jujube skin. The jujube red pigment extracted by membrane separation technology has good stability and high purity; and the production process is simple, easy to operate, and has important practical application in food, medical treatment and health care. value and show broad application prospects.

Description of drawings

Fig. 1 is the process flow diagram of extracting jujube red pigment from dry jujube skin of the present invention;

Fig. 2 is an ultraviolet-visible absorption spectrum diagram of jujube red pigment extracted from dried red jujube skin of the present invention.

detailed description

The present invention will be further described below in conjunction with specific embodiments and drawings, but the present invention is not limited to the following embodiments. The methods and reagents are conventional methods unless otherwise specified, and the raw materials and equipment can be obtained from public commercial sources unless otherwise specified.

The most prominent feature of the present invention is that the jujube red pigment in the dried jujube skin is separated by means of membrane filtration through the polysaccharide-removed dry jujube skin extract. Membrane filtration can filter out polysaccharides and some other macromolecular impurities that have not been removed.

And the inventor of the present case also made the process of the present invention obtain higher purity and safer bougainvillea pigment by setting the parameters of the steps of ultrasonography, cleaning, soaking and polysaccharide removal.

Example 1:

According to the technical scheme of the present invention, the following dry jujube bark can be used to extract the jujube red pigment.

1. The cleaned raw materials are boiled at 100° C. (or boiling) for 30 minutes, washed with water to remove jujube meat and other impurities, and the obtained jujube skin is soaked with 3% (v/v) HCl for 10 minutes, and the ratio of solid to liquid is 1 : 20 (g/ml), washed to remove HCl, dried at 40°C for 12 hours, crushed with a pulverizer, and passed through a 40-mesh sieve;

2. The ultrasonic power is 60w, the time is 45min, the temperature is 60°C, the ratio of material to liquid is 1:20 (g/ml), and 0.8% (w/v) NaOH solution is used as the extraction solution, centrifuged at 10000rpm for 30min, and the precipitate is discarded. Adjust the pH of the supernatant to 7.0;

3. The neutral supernatant is concentrated under reduced pressure to 25% of the volume of the stock solution at a vacuum degree of -0.02 to -0.08MPa and a temperature of 50 to 60°C, and then added with absolute ethanol with a volume of 75% of the stock solution, at -20 Precipitate at ℃ for 30 minutes, centrifuge at 10,000 rpm for 30 minutes, remove polysaccharides, and obtain an extract;

4. (1) The extract is centrifuged at 10,000rpm for 30min to pass through an ultrafiltration membrane with a molecular weight cut-off of 30KDa to obtain the effluent ①;

(2) The effluent ① is centrifuged at 10,000 rpm for 30 min to pass through an ultrafiltration membrane with a molecular weight cut-off of 2KDa to obtain the effluent ②.

The effluent ② was dried at 40° C. for 18 hours to obtain boar red pigment.

Example 2:

1) Take the dried jujube skin and crush it, wherein the dried jujube is washed first, then steamed at 100°C for 15 minutes, washed with water to remove jujube meat and other impurities, and the obtained jujube skin is obtained;

Soak in 1% (v/v) HCl for 8 minutes, the ratio of solid to liquid is 0.8:18 (g/ml), wash to remove HCl, dry at 35°C to constant weight, crush with a pulverizer, and pass through 40~ 60 mesh sieve.

2) Immerse the crushed dried red jujube skin into an alkaline solution and combine it with ultrasonic extraction to obtain dried red jujube skin extract; the ultrasonic power is 70w, the time is 45min, the temperature is 50°C, and the ratio of solid to liquid is 1.2:22( g/ml), using 0.9% (w/v) NaOH solution as the extract, centrifuging at 8000 rpm for 25 min, discarding the precipitate, and adjusting the pH value of the supernatant to 7.0.

3) Use absolute ethanol to remove polysaccharides from the extract, concentrate the neutral supernatant under reduced pressure at 50°C to 30% of the volume of the original solution, add anhydrous ethanol with a volume of 70% of the original solution, and precipitate at -25°C 60 minutes, then centrifuged at a speed of 10000 rpm for 35 minutes, and then the polysaccharide was removed to obtain an extract.

4) After centrifuging the polysaccharide-treated extract, pass it through an ultrafiltration membrane with a molecular weight cut-off of 35 KDa to obtain a primary effluent.

5) The primary effluent is centrifuged again, and then passed through an ultrafiltration membrane with a molecular weight cut-off of 1 KDa to obtain the final effluent.

6) Dry the final effluent at 40° C. to a constant weight to obtain the boar red pigment.

Example 3:

1) Take the dried jujube skin and crush it, wherein the dried jujube is washed first, then steamed at 100°C for 25 minutes, washed with water to remove jujube meat and other impurities, and the obtained jujube skin is obtained;

Soak in 5% (v/v) HCl for 12 minutes, the ratio of solid to liquid is 1.2:22 (g/ml), wash to remove HCl, dry at 50°C to constant weight, crush with a pulverizer, pass through 40 mesh screen.

2) Immerse the crushed dried jujube skin into an alkaline solution, and combine it with ultrasonic extraction to obtain an extract of dried jujube skin; the ultrasonic power is 40w, the time is 60min, the temperature is 60°C, and the ratio of solid to liquid is 0.8:22( g/ml), using 0.8% (w/v) NaOH solution as the extract, centrifuging at 9000 rpm for 35 min, discarding the precipitate, and adjusting the pH of the supernatant to 7.0.

3) Use absolute ethanol to remove polysaccharides from the extract, concentrate the neutral supernatant under reduced pressure at 60°C to 20% of the volume of the original solution, add anhydrous ethanol with 70% of the volume of the original solution, and precipitate at -15°C 50min, then centrifuged at 9000rpm for 25min, and then the polysaccharide was removed to obtain the extract.

4) After centrifuging the polysaccharide-treated extract, pass it through an ultrafiltration membrane with a molecular weight cut-off of 25 KDa to obtain a primary effluent.

5) The primary effluent is centrifuged again, and then passed through an ultrafiltration membrane with a molecular weight cut-off of 3KDa to obtain the final effluent.

6) Dry the final effluent at 45° C. to a constant weight to obtain boar red pigment.

Example 4:

1) Take the dried jujube skin and crush it, wherein the dried jujube is washed first, then steamed at 100°C for 25 minutes, washed with water to remove jujube meat and other impurities, and the obtained jujube skin is obtained;

Soak in 4% (v/v) HCl for 11 minutes, the ratio of solid to liquid is 1.2:18 (g/ml), wash to remove HCl, dry at 45°C to constant weight, pulverize with a pulverizer, pass through 40 mesh screen

2) Immerse the crushed dried red jujube skin into an alkaline solution and combine it with ultrasonic extraction to obtain dried red jujube skin extract; the ultrasonic power is 65w, the time is 50min, the temperature is 55°C, and the ratio of solid to liquid is 0.8:22( g/ml), using 0.85% (w/v) NaOH solution as the extract, centrifuging at 9000 rpm for 30 min, discarding the precipitate, and adjusting the pH value of the supernatant to 7.0.

3) Use absolute ethanol to remove polysaccharides from the extract, concentrate the neutral supernatant under reduced pressure at 55°C to 27% of the volume of the original solution, add absolute ethanol with a volume of 73% of the original solution, and precipitate at -20°C 50min, then centrifuged at a speed of 8500rpm for 32min, and then the polysaccharide was removed to obtain an extract.

4) After centrifuging the polysaccharide-treated extract, pass it through an ultrafiltration membrane with a molecular weight cut-off of 30KDa to obtain a primary effluent.

5) The primary effluent is centrifuged again, and then passed through an ultrafiltration membrane with a molecular weight cut-off of 2KDa to obtain the final effluent.

6) Dry the final effluent at 40° C. to a constant weight to obtain the boar red pigment.

Example 5:

1) Take the dried jujube skin and crush it, wherein the dried jujube is first cleaned, then boiled in water for 25 minutes, washed to remove jujube meat and other impurities, and the obtained jujube skin is obtained;

Soak in 2% (v/v) HCl for 9 minutes, the ratio of solid to liquid is 0.9:21 (g/ml), wash to remove HCl, dry at 35°C to constant weight, crush with a pulverizer, pass through 40 mesh screen.

2) Immerse the crushed dried jujube skin into an alkaline solution, and combine it with ultrasonic extraction to obtain a dry jujube skin extract; the ultrasonic power is 60w, the time is 45min, the temperature is 50°C, and the ratio of solid to liquid is 1:20 ( g/ml), using 0.8% (w/v) NaOH solution as the extract, centrifuged at 10,000 rpm for 30 min, discarded the precipitate, and adjusted the pH value of the supernatant to 7.0.

3) Use absolute ethanol to remove polysaccharides from the extract, concentrate the neutral supernatant under reduced pressure at 50°C to 30% of the volume of the original solution, add anhydrous ethanol with a volume of 70% of the original solution, and precipitate at -21°C 60min, then centrifuged at a speed of 10000rpm for 30min, and then the polysaccharide was removed to obtain an extract.

4) After centrifuging the polysaccharide-treated extract, pass it through an ultrafiltration membrane with a molecular weight cut-off of 30KDa to obtain a primary effluent.

5) The primary effluent is centrifuged again, and then passed through an ultrafiltration membrane with a molecular weight cut-off of 2KDa to obtain the final effluent.

6) Dry the final effluent at 40° C. to a constant weight to obtain the boar red pigment.

The performance of the bougainvillea pigment obtained using the method of the present invention is tested below.

1.1 Calculation of the boar red pigment yield:

Accurately weigh a certain amount of jujube skin powder, extract and dry through membrane separation, accurately weigh the quality of the jujube pigment, and calculate the yield of the jujube pigment according to the following formula:

Yield = (mass of jujube red pigment/mass of jujube skin powder) × 100%

1.2 The ultraviolet-visible absorption spectrum of the red pigment:

The bougainvillea pigment was prepared into an aqueous solution with a concentration of 0.5 mg/mL, and distilled water was used as a blank control to carry out full-wavelength ultraviolet-visible absorption spectrum analysis to determine the maximum absorption wavelength.

1.3 Determination of the color value of the date red pigment:

Prepare the jujube red pigment into an aqueous solution with a concentration of 0.5 mg/mL, use distilled water as a blank control, measure the absorbance at the maximum absorption wavelength, and calculate the color value of the jujube red pigment according to the following formula:

E=A/m

In the formula, A is the absorbance; m is the mass (g) of the sample; E is the color value.

1.4 Research on physicochemical properties of jujube red pigment:

1.4.1 Solubility

The jujube red pigment was added into water with pH values of 3, 7, and 11 respectively according to the mass concentration of 0.5 mg/mL, and fully oscillated; the solvent without jujube red pigment was used as a blank control, and measured at the maximum absorption wavelength Absorbance, combined with the color change of the solution, compares the solubility of the red pigment in aqueous solutions with different pH values.

1.4.2 Thermal stability

The neutral aqueous solution of bougainvillea pigment (pH 7) with a mass concentration of 0.5 mg/mL was heated at 80°C for 24 hours, then rapidly cooled to room temperature, and the absorbance was measured at the maximum absorption wavelength, and the change of absorbance before and after heating was compared.

2. Results and Analysis

2.1 The yield of the boar red pigment:

According to the formula for calculating the yield, under the extraction conditions described in the present invention, the yield of bougainvillea is 4.56%.

2.2 The ultraviolet-visible absorption spectrum of the red pigment:

As shown in Fig. 2, the ultraviolet-visible absorption spectrum of the purplish red pigment of the present invention has a maximum absorption peak at 273nm, which is consistent with the previously reported purplish red pigment spectrum.

2.3 The color value of the boar red pigment:

According to the formula for calculating the color value, under the extraction conditions described in the present invention, the color value of the date red pigment is 11.7, which has reached the food additive standard.

2.4 Physicochemical properties of the bougainvillea pigment:

2.4.1 Solubility of the boar red pigment:

As shown in Table 1, the jujube red pigment of the present invention is soluble in strong acid (pH value is 3), neutral (pH value is 7) and strongly alkaline (pH value is 11) aqueous solution, and color is respectively: orange red, jujube Red and deep maroon, the absorbance changes little, and there is no fading phenomenon, indicating that the pH value has little effect on the stability of the purplish red pigment, which is consistent with the previously reported conclusions.

The dissolubility of the bougainvillea pigment described in table 1

2.4.2 The thermal stability of the boar red pigment:

As shown in Table 2, when the purplish red pigment of the present invention is heated at 80°C for 24 hours, the absorbance increases by 6.5%, and no fading occurs, indicating that the purplish red pigment has good thermal stability.

The thermostability of bordeaux red pigment described in table 2

The above shows that the jujube red pigment extracted according to the process of the present invention has good stability and high purity, and has broad market prospects.

Although the embodiment of the present invention has been disclosed as above, it is not limited to the use listed in the specification and implementation, it can be applied to various fields suitable for the present invention, and it can be easily understood by those skilled in the art Therefore, the invention is not limited to the specific details and examples shown and described herein without departing from the general concept defined by the claims and their equivalents.

Claims (7)

1. a kind of dry jujube peel extracts the technology of jujube red pigment, it is characterized in that, the dry red jujube peel extracting solution through membrane filtration is separated the red pigment in the dry red jujube peel through removing polysaccharide, comprises the following steps: 1) take dry jujube skin, pulverize; 2) immersing the crushed dried red jujube skin into an alkaline solution, combined with ultrasonic extraction, to obtain an extract of dried red jujube skin; 3) using absolute ethanol to remove polysaccharides from the extract; 4) After centrifuging the polysaccharide-treated extract, pass it through an ultrafiltration membrane with a molecular weight cut-off of 25-35 KDa to obtain a primary effluent; 5) After the primary effluent is centrifuged again, it passes through an ultrafiltration membrane with a molecular weight cut-off of 1 to 3 KDa to obtain the final effluent; 6) drying the final effluent to a constant weight to obtain the boar red pigment; Said step 1) includes: Wash the dried red dates first, then cook them at 100°C for 15-30 minutes, wash them with water to remove the jujube meat and other impurities, and obtain the jujube skins; Soak in 1% to 5% (v/v) HCl for 8 to 12 minutes, the ratio of solid to liquid is 0.8 to 1.2:18 to 22 (g/ml), wash to remove HCl, and dry at 35 to 50°C until Constant weight, pulverize with a pulverizer, and sieve; Said step 2) includes: The ultrasonic power is 40-70w, the time is 45-60min, the temperature is 50-60°C, the ratio of material to liquid is 0.8-1.2:18-22 (g/ml), and 0.7-0.9% (w/v) NaOH solution To obtain the extract, centrifuge at a speed of 8000-10000 rpm for 25-35 minutes, discard the precipitate, and adjust the pH value of the supernatant to 7.0. 2. the technique for extracting jujube red pigment from dry red jujube skin as claimed in claim 1 is characterized in that, under 100 ℃ of conditions, cooking 30min, the time of soaking with the HCl treatment of 3% (v/v) is 10min, and solid-liquid ratio The ratio is 1:20 (g/ml), and dried at 40°C to constant weight, and passed through a 40-mesh sieve. 3. the technique for extracting jujube red pigment from dry jujube skin as claimed in claim 1, is characterized in that, in described step 2), ultrasonic power is 60w, time is 45min, temperature is 60 ℃, and solid-liquid ratio is 1: 20 (g/ml), using 0.8% (w/v) NaOH solution as the extraction solution, centrifuged at a speed of 10000 rpm for 30 min. 4. The process for extracting jujube red pigment from dried jujube skin as claimed in claim 1, characterized in that, said step 3) comprises: the neutral supernatant is concentrated under reduced pressure at 50-60°C to 25-25% of the volume of the stock solution. 30%, adding absolute ethanol with 70-75% volume of the original solution, precipitation at -15-25°C for 30-60 minutes, and centrifugation at 8000-10000 rpm for 25-35 minutes, and then removing polysaccharides to obtain an extract. 5. The process of extracting jujube red pigment from dried jujube skin as claimed in claim 4, wherein the neutral supernatant is decompressed at a vacuum degree of -0.02～-0.08MPa and a temperature of 50～60°C Concentrate to 25% of the volume of the original solution, add absolute ethanol with a volume of 75% of the original solution, precipitate at -20°C for 30 minutes, and centrifuge at 10,000 rpm for 30 minutes. 6. the technique that dried jujube skin extracts jujube red pigment as claimed in claim 1 is characterized in that, in described step 4), the extract after polysaccharide treatment is centrifuged 30min with the speed of 10000rpm, is 30KDa ultracentrifuge by this molecular weight cut-off filter membrane to obtain the primary effluent. 7. the technique of extracting jujube red pigment from dry jujube skin as claimed in claim 6, is characterized in that, in described step 5), the primary effluent liquid is centrifugal 30min with the speed of 10000rpm, is the ultrafiltration membrane of 2KDa by molecular weight cut-off, obtains The final effluent, the final effluent was dried at 40°C.